RH-53/54
Nokia Customer Care 8-System Module
22 COMPANY CONFIDENTIAL Issue 2 06/2005
Copyright © 2005 Nokia. All Rights Reserved.
Functional Description
Audio External
RH-53/54 is designed to support fully differential external audio accessory connection. A head-
set and PnPHF can be directly connected to system connector. Detection of the different ac-
cessories is made in analog way by reading the DC voltage value of EAD converter.
Figure 4:External audio interface
Headset Detection
Supported headsets are 4-wire fully differential accessories. The hardware used to detect ac-
cessories is contained in the UEM and BB area. For interrupt purposes the UEM inputs
HOOKINT and HEADINT are used. The bottom connector contains a switch, which opens
when an accessory is connected. The switch is routed to the UEM HEADINT input.
The current generators on the HOOKINT and HEADINT pins acts as internally pull-up resistors
with values equivalent to 675 k - 2.86 M, tolerances of the current source and VFLASH1 con-
sidered. The HOOKINT input comparator threshold level can be set to two different values.
Levels can be found in the table.
1k0
Hookint
Headint
Headint
EAD
MICB2
MIC2P
MIC2N
33N
HFCM
HF
Bottom
Connector
UEM
2.1V
2.7V
33N
1k0
MBUS
MicGnd
1.8V
0.3V
0.8V
3...25k
Mic_bias
0.8V
Not all components are shown
To Next Page
Loading...
